PHP 8.5.0 Alpha 2 available for testing

The SplMinHeap class

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

Вступ

The SplMinHeap class provides the main functionalities of a heap, keeping the minimum on the top.

Короткий огляд класу

class SplMinHeap extends SplHeap {
/* Методи */
protected compare(mixed $value1, mixed $value2): int
/* Успадковані методи */
protected SplHeap::compare(mixed $value1, mixed $value2): int
public SplHeap::insert(mixed $value): true
public SplHeap::key(): int
}

Зміст

  • SplMinHeap::compare — Compare elements in order to place them correctly in the heap while sifting up
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User Contributed Notes 2 notes

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3
gom
5 years ago
I experimented what happens when arrays are inserted:

<?php
$heap
= new SplMinHeap();
$heap->insert([22,333]);
$heap->insert([2,33]);
$heap->insert([222,3]);

var_export($heap->extract());
echo
'<br>';
var_export($heap->extract());
echo
'<br>';
var_export($heap->extract());
?>

Output:

array ( 0 => 2, 1 => 33, )
array ( 0 => 22, 1 => 333, )
array ( 0 => 222, 1 => 3, )
up
0
andy at nospam dot airslash dot net
10 days ago
To expand on gom's comment, SplMinHeap will also take into account the subsequent elements of the array you inserted, if the elements before that are equal.

<?php
$heap
= new SplMinHeap();
$heap->insert([0, 10]);
$heap->insert([0, 30]);
$heap->insert([0, 15]);
while (!
$heap->isEmpty()) {
[
$a, $b] = $heap->extract();
echo
"a:$a, b:$b\n";
}
echo
"---\n";
$heap->insert([0, 10, 100]);
$heap->insert([0, 10, 300]);
$heap->insert([0, 10, 150]);
while (!
$heap->isEmpty()) {
[
$a, $b, $c] = $heap->extract();
echo
"a:$a, b:$b, c:$c\n";
}
?>

will output:

a:0, b:10
a:0, b:15
a:0, b:30
---
a:0, b:10, c:100
a:0, b:10, c:150
a:0, b:10, c:300
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